Sample selection protocol:
Stationary and Travelling trips
Complete checklists (report all species)
Drop duplicates from group trips.
Drop trips with 1 bird
Duration between 5-240 mins
Notes:
We select cities first, and then users. This gives us the same users in each pre/post period (in 2020) with the caveat that users mobility is limited to the top X cities.
Few people take stationary trips pre-lockdown.
Number of users is the count of unique user ID’s active on a given day.
Subset of top 20 cities in which users meeting participation constraint are present.
| COUNTY | STATE | POP_DENSITY |
|---|---|---|
| North East Delhi | Delhi | 36155.226 |
| Central Delhi | Delhi | 27729.524 |
| East Delhi | Delhi | 27132.476 |
| Chennai | Tamil Nadu | 26552.754 |
| Kolkata | West Bengal | 24306.454 |
| Mumbai Suburban | Maharashtra | 20979.735 |
| Mumbai | Maharashtra | 19652.299 |
| West Delhi | Delhi | 19563.408 |
| Hyderabad | Telangana | 18171.995 |
| Rangareddy | Telangana | 18171.995 |
| South Delhi | Delhi | 11060.441 |
| North Delhi | Delhi | 8254.038 |
| North West Delhi | Delhi | 8254.038 |
| New Delhi | Delhi | 5446.456 |
| South West Delhi | Delhi | 5446.456 |
| Bangalore | Karnataka | 4381.398 |
| Haora | West Bengal | 3306.087 |
| North 24 Parganas | West Bengal | 2444.988 |
| South 24 Parganas | West Bengal | 819.474 |
| PREPOST | Num. Trips | Num. Cities | Num. Users | Num. Species |
|---|---|---|---|---|
| Before | 8561 | 269 | 542 | 1010 |
| After | 14858 | 167 | 542 | 778 |
| PREPOST | Num. Trips | Num. Cities | Num. Users | Num. Species |
|---|---|---|---|---|
| Before | 1376 | 19 | 103 | 387 |
| After | 2699 | 17 | 103 | 284 |
This table shows trip statistics before and after lockdown among users meeting the participation constraint.
| PREPOST | Trip Length | Mean Species Richness | Median Species Richness |
|---|---|---|---|
| Before | 37.72492 | 17.09064 | 13 |
| After | 25.90759 | 13.35947 | 12 |
| PREPOST | Trip Length | Mean Species Richness | Median Species Richness |
|---|---|---|---|
| Before | 36.84956 | 15.58939 | 11 |
| After | 25.71212 | 12.97925 | 12 |
Marginal species are species observed after lockdown which were not observed before lockdown. To implement: in each city, obtain list of species before and after lockdown observed by users meeting participation cosntraint. Extract species in “after” list not in “before” list.
| TAXONOMIC.ORDER | COMMON.NAME | SCIENTIFIC.NAME | COUNTY |
|---|---|---|---|
| 11515 | falcon sp. | Falco sp. | Kolkata |
| 7173 | white egret sp. | Ardea/Egretta/Bubulcus sp. | Kolkata |
| 4071 | swift sp. | Apodidae sp. | Kolkata |
| 22694 | Blyth’s Reed Warbler | Acrocephalus dumetorum | Kolkata |
| 9306 | Common Kingfisher | Alcedo atthis | Kolkata |
| 7140 | Little Egret | Egretta garzetta | Kolkata |
| 7689 | Shikra | Accipiter badius | Kolkata |
| 8110 | Barn Owl | Tyto alba | Kolkata |
| 6863 | Asian Openbill | Anastomus oscitans | Kolkata |
| 10734 | Fulvous-breasted Woodpecker | Dendrocopos macei | Kolkata |
| 30542 | Paddyfield Pipit | Anthus rufulus | Kolkata |
| 5341 | Gray-headed Swamphen | Porphyrio poliocephalus | Kolkata |
| 22558 | Zitting Cisticola | Cisticola juncidis | Kolkata |
| 10971 | Rufous Woodpecker | Micropternus brachyurus | Kolkata |
| 30145 | Scaly-breasted Munia | Lonchura punctulata | Kolkata |
| 7398 | Oriental Honey-buzzard | Pernis ptilorhynchus | Kolkata |
| 5274 | Eurasian Moorhen | Gallinula chloropus | Kolkata |
| 20680 | Large-billed Crow | Corvus macrorhynchos | Kolkata |
| 11734 | Red-breasted Parakeet | Psittacula alexandri | Kolkata |
| 28406 | Taiga Flycatcher | Ficedula albicilla | South 24 Parganas |
| 26795 | Jungle Myna | Acridotheres fuscus | South 24 Parganas |
| 23519 | Red-whiskered Bulbul | Pycnonotus jocosus | South 24 Parganas |
| 7689 | Shikra | Accipiter badius | South 24 Parganas |
| 8584 | Spotted Owlet | Athene brama | South 24 Parganas |
| 22694 | Blyth’s Reed Warbler | Acrocephalus dumetorum | South 24 Parganas |
| 11708 | Alexandrine Parakeet | Psittacula eupatria | South 24 Parganas |
| 10971 | Rufous Woodpecker | Micropternus brachyurus | South 24 Parganas |
| 8110 | Barn Owl | Tyto alba | South 24 Parganas |
| 18754 | Indian Golden Oriole | Oriolus kundoo | South 24 Parganas |
| 30131 | White-rumped Munia | Lonchura striata | South 24 Parganas |
| 21611 | Bengal Bushlark | Mirafra assamica | South 24 Parganas |
| 11715 | Rose-ringed Parakeet | Psittacula krameri | West Delhi |
| 25417 | Jungle Babbler | Turdoides striata | West Delhi |
| 2009 | Laughing Dove | Streptopelia senegalensis | West Delhi |
| 24645 | Indian White-eye | Zosterops palpebrosus | West Delhi |
| 19538 | Black Drongo | Dicrurus macrocercus | West Delhi |
| 22366 | prinia sp. | Prinia sp. | West Delhi |
| 7268 | Glossy Ibis | Plegadis falcinellus | Bangalore |
| 466 | Indian Spot-billed Duck | Anas poecilorhyncha | Bangalore |
| 24366 | Yellow-eyed Babbler | Chrysomma sinense | Bangalore |
| 26773 | Chestnut-tailed Starling | Sturnia malabarica | Bangalore |
| 30126 | Indian Silverbill | Euodice malabarica | Bangalore |
| 4071 | swift sp. | Apodidae sp. | Bangalore |
| 7264 | heron sp. | Ardeidae sp. | Bangalore |
| 7319 | ibis sp. | Threskiornithidae sp. (ibis sp.) | Bangalore |
| 3303 | Common Hawk-Cuckoo | Hierococcyx varius | Bangalore |
| 26906 | myna/starling sp. | Sturnidae sp. | Bangalore |
| 12547 | parakeet sp. | Psittaciformes sp. (parakeet sp.) | Bangalore |
| 11708 | Alexandrine Parakeet | Psittacula eupatria | Bangalore |
| 7569 | Booted Eagle | Hieraaetus pennatus | Bangalore |
| 7564 | Greater Spotted Eagle | Clanga clanga | Bangalore |
| 30329 | House Sparrow | Passer domesticus | Bangalore |
| 7398 | Oriental Honey-buzzard | Pernis ptilorhynchus | Bangalore |
| 416 | Garganey | Spatula querquedula | Bangalore |
| 20517 | Rufous Treepie | Dendrocitta vagabunda | Bangalore |
| 3083 | Blue-faced Malkoha | Phaenicophaeus viridirostris | Bangalore |
| 9197 | Indian Gray Hornbill | Ocyceros birostris | Bangalore |
| 28957 | flowerpecker sp. | Prionochilus/Dicaeum sp. | Bangalore |
| 7301 | Red-naped Ibis | Pseudibis papillosa | Bangalore |
| 11012 | Black-rumped Flameback | Dinopium benghalense | Bangalore |
| 1330 | Gray Francolin | Francolinus pondicerianus | Bangalore |
| 27943 | Blue-throated Flycatcher | Cyornis rubeculoides | Bangalore |
| 22366 | prinia sp. | Prinia sp. | Bangalore |
| 27863 | Oriental Magpie-Robin | Copsychus saularis | Bangalore |
| 9785 | bee-eater sp. | Merops sp. | Bangalore |
| 3260 | Gray-bellied Cuckoo | Cacomantis passerinus | Bangalore |
| 7028 | cormorant sp. | Phalacrocoracidae sp. | Bangalore |
| 8078 | eagle sp. | Accipitridae sp. (eagle sp.) | Bangalore |
| 34501 | bird sp. | Aves sp. | Bangalore |
| 23150 | Dusky Crag-Martin | Ptyonoprogne concolor | Bangalore |
| 688 | duck sp. | Anatinae sp. | Bangalore |
| 19565 | Black/Ashy Drongo | Dicrurus macrocercus/leucophaeus | Bangalore |
| 7058 | Yellow Bittern | Ixobrychus sinensis | Bangalore |
| 30126 | Indian Silverbill | Euodice malabarica | Mumbai |
| 27856 | Indian Robin | Copsychus fulicatus | Mumbai |
| 22694 | Blyth’s Reed Warbler | Acrocephalus dumetorum | Mumbai |
| 3023 | Greater Coucal | Centropus sinensis | Mumbai |
| 25417 | Jungle Babbler | Turdoides striata | Mumbai |
| 7868 | Black Kite | Milvus migrans | Mumbai |
| 6979 | Indian Cormorant | Phalacrocorax fuscicollis | Mumbai |
| 7689 | Shikra | Accipiter badius | Mumbai |
| 6863 | Asian Openbill | Anastomus oscitans | Mumbai |
| 5890 | Little Stint | Calidris minuta | Mumbai |
| 24044 | Phylloscopus sp. | Phylloscopus sp. | Mumbai |
| 30522 | wagtail sp. | Motacilla sp. | Mumbai |
| 7880 | Brahminy Kite | Haliastur indus | Mumbai |
| 6956 | Little Cormorant | Microcarbo niger | Mumbai |
| 232 | Lesser Whistling-Duck | Dendrocygna javanica | North 24 Parganas |
| 18851 | Ashy Woodswallow | Artamus fuscus | North 24 Parganas |
| 4010 | Little Swift | Apus affinis | North 24 Parganas |
| 20667 | Large-billed Crow | Corvus macrorhynchos | East Delhi |
| 1139 | Indian Peafowl | Pavo cristatus | East Delhi |
| 26755 | Rosy Starling | Pastor roseus | East Delhi |
| 9753 | Green Bee-eater | Merops orientalis | East Delhi |
| 9474 | White-throated Kingfisher | Halcyon smyrnensis | East Delhi |
| 7301 | Red-naped Ibis | Pseudibis papillosa | East Delhi |
| 23805 | Hume’s Warbler | Phylloscopus humei | East Delhi |
| 26787 | Bank Myna | Acridotheres ginginianus | East Delhi |
| 3023 | Greater Coucal | Centropus sinensis | East Delhi |
| 6965 | Great Cormorant | Phalacrocorax carbo | East Delhi |
| 22267 | Gray-breasted Prinia | Prinia hodgsonii | East Delhi |
| 18754 | Indian Golden Oriole | Oriolus kundoo | East Delhi |
| 30329 | House Sparrow | Passer domesticus | East Delhi |
| 7117 | Purple Heron | Ardea purpurea | East Delhi |
| 7563 | Indian Spotted Eagle | Clanga hastata | East Delhi |
| 466 | Indian Spot-billed Duck | Anas poecilorhyncha | East Delhi |
| 6869 | Woolly-necked Stork | Ciconia episcopus | East Delhi |
| 7175 | Indian Pond-Heron | Ardeola grayii | East Delhi |
| 28408 | Red-breasted Flycatcher | Ficedula parva | East Delhi |
| 7140 | Little Egret | Egretta garzetta | East Delhi |
| 7689 | Shikra | Accipiter badius | East Delhi |
| 4010 | Little Swift | Apus affinis | East Delhi |
| 7100 | Gray Heron | Ardea cinerea | East Delhi |
| 6979 | Indian Cormorant | Phalacrocorax fuscicollis | East Delhi |
| 5972 | Green Sandpiper | Tringa ochropus | East Delhi |
| 34500 | passerine sp. | Passeriformes sp. | East Delhi |
| 4071 | swift sp. | Apodidae sp. | East Delhi |
| 28467 | Black Redstart | Phoenicurus ochruros | East Delhi |
| 7381 | Egyptian Vulture | Neophron percnopterus | East Delhi |
| 7319 | ibis sp. | Threskiornithidae sp. (ibis sp.) | East Delhi |
| 24287 | Lesser Whitethroat | Sylvia curruca | East Delhi |
| 26772 | Brahminy Starling | Sturnia pagodarum | South Delhi |
| 25394 | Large Gray Babbler | Turdoides malcolmi | South Delhi |
| 24645 | Indian White-eye | Zosterops palpebrosus | South Delhi |
| 26755 | Rosy Starling | Pastor roseus | South Delhi |
| 23805 | Hume’s Warbler | Phylloscopus humei | South Delhi |
| 5654 | Red-wattled Lapwing | Vanellus indicus | South Delhi |
| 1139 | Indian Peafowl | Pavo cristatus | South Delhi |
| 27856 | Indian Robin | Copsychus fulicatus | South Delhi |
| 30329 | House Sparrow | Passer domesticus | South Delhi |
| 2004 | Spotted Dove | Streptopelia chinensis | Chennai |
| 29407 | sunbird sp. | Nectariniidae sp. (sunbird sp.) | Chennai |
| 7173 | white egret sp. | Ardea/Egretta/Bubulcus sp. | Chennai |
| 3023 | Greater Coucal | Centropus sinensis | Chennai |
| 8883 | owl sp. | Strigiformes sp. | Chennai |
| 22188 | Common Tailorbird | Orthotomus sutorius | Chennai |
| 7398 | Oriental Honey-buzzard | Pernis ptilorhynchus | Chennai |
| 9774 | Blue-tailed Bee-eater | Merops philippinus | Chennai |
| 27308 | Orange-headed Thrush | Geokichla citrina | Chennai |
| 23596 | White-browed Bulbul | Pycnonotus luteolus | Chennai |
| 6863 | Asian Openbill | Anastomus oscitans | Chennai |
| 22305 | Ashy Prinia | Prinia socialis | Chennai |
| 22322 | Plain Prinia | Prinia inornata | Chennai |
| 9698 | Pied Kingfisher | Ceryle rudis | Chennai |
| 30126 | Indian Silverbill | Euodice malabarica | Chennai |
| 26760 | Asian Pied Starling | Gracupica contra | Chennai |
| 7069 | Black Bittern | Ixobrychus flavicollis | Chennai |
| 30329 | House Sparrow | Passer domesticus | Chennai |
| 30472 | Western Yellow Wagtail | Motacilla flava | Chennai |
| 6510 | tern sp. | Sterninae sp. | Chennai |
| 4071 | swift sp. | Apodidae sp. | Chennai |
| 4010 | Little Swift | Apus affinis | Chennai |
| 3168 | Asian Koel | Eudynamys scolopaceus | South West Delhi |
| 7100 | Gray Heron | Ardea cinerea | South West Delhi |
| 4010 | Little Swift | Apus affinis | South West Delhi |
| 30329 | House Sparrow | Passer domesticus | South West Delhi |
| 466 | Indian Spot-billed Duck | Anas poecilorhyncha | South West Delhi |
| 26787 | Bank Myna | Acridotheres ginginianus | South West Delhi |
| 26755 | Rosy Starling | Pastor roseus | South West Delhi |
| 7301 | Red-naped Ibis | Pseudibis papillosa | South West Delhi |
| 19538 | Black Drongo | Dicrurus macrocercus | South West Delhi |
| 7506 | Short-toed Snake-Eagle | Circaetus gallicus | South West Delhi |
| 6965 | Great Cormorant | Phalacrocorax carbo | South West Delhi |
| 27862 | Oriental Magpie-Robin | Copsychus saularis | South West Delhi |
| 20517 | Rufous Treepie | Dendrocitta vagabunda | South West Delhi |
| 23519 | Red-whiskered Bulbul | Pycnonotus jocosus | South West Delhi |
| 22305 | Ashy Prinia | Prinia socialis | South West Delhi |
| 19650 | drongo sp. | Dicrurus sp. | South West Delhi |
| 7868 | Black Kite | Milvus migrans | South West Delhi |
| 28694 | Brown Rock Chat | Oenanthe fusca | South West Delhi |
| 27969 | Tickell’s Blue Flycatcher | Cyornis tickelliae | Hyderabad |
| 7170 | Cattle Egret | Bubulcus ibis | Hyderabad |
| 28789 | Thick-billed Flowerpecker | Dicaeum agile | Hyderabad |
| 20517 | Rufous Treepie | Dendrocitta vagabunda | Hyderabad |
| 28861 | Thick-billed/Pale-billed Flowerpecker | Dicaeum agile/erythrorhynchos | Hyderabad |
| 23311 | swallow sp. | Hirundinidae sp. | Hyderabad |
| 20667 | Large-billed Crow | Corvus macrorhynchos | Hyderabad |
| 1139 | Indian Peafowl | Pavo cristatus | Hyderabad |
| 23153 | Barn Swallow | Hirundo rustica | Hyderabad |
| 30503 | White-browed Wagtail | Motacilla maderaspatensis | Hyderabad |
| 23150 | Dusky Crag-Martin | Ptyonoprogne concolor | Hyderabad |
| 6481 | River Tern | Sterna aurantia | Hyderabad |
| 3260 | Gray-bellied Cuckoo | Cacomantis passerinus | Hyderabad |
| 11376 | Eurasian Kestrel | Falco tinnunculus | Hyderabad |
| 27856 | Indian Robin | Copsychus fulicatus | Hyderabad |
| 7268 | Glossy Ibis | Plegadis falcinellus | Hyderabad |
| 26755 | Rosy Starling | Pastor roseus | Hyderabad |
| 7175 | Indian Pond-Heron | Ardeola grayii | Hyderabad |
| 12547 | parakeet sp. | Psittaciformes sp. (parakeet sp.) | Hyderabad |
| 30468 | Gray Wagtail | Motacilla cinerea | Hyderabad |
| 11516 | diurnal raptor sp. | Accipitriformes/Falconiformes sp. | Hyderabad |
| 1798 | Rock Pigeon | Columba livia | Hyderabad |
| 30472 | Western Yellow Wagtail | Motacilla flava | Hyderabad |
| 7140 | Little Egret | Egretta garzetta | Hyderabad |
| 9197 | Indian Gray Hornbill | Ocyceros birostris | Hyderabad |
| 27943 | Blue-throated Flycatcher | Cyornis rubeculoides | Haora |
| 23153 | Barn Swallow | Hirundo rustica | Haora |
| 9474 | White-throated Kingfisher | Halcyon smyrnensis | Haora |
| 25417 | Jungle Babbler | Turdoides striata | Haora |
| 27664 | Asian Brown Flycatcher | Muscicapa dauurica | Haora |
| 1968 | Eurasian Collared-Dove | Streptopelia decaocto | Haora |
| 4045 | Asian Palm-Swift | Cypsiurus balasiensis | Haora |
| 23932 | Large-billed Leaf Warbler | Phylloscopus magnirostris | Haora |
| 20680 | Large-billed Crow | Corvus macrorhynchos | Haora |
| 7130 | Intermediate Egret | Ardea intermedia | Haora |
| 7170 | Cattle Egret | Bubulcus ibis | Haora |
| 3023 | Greater Coucal | Centropus sinensis | Haora |
| 23906 | Green-crowned Warbler | Phylloscopus burkii | Haora |
| 23922 | Greenish Warbler | Phylloscopus trochiloides | Haora |
| 20517 | Rufous Treepie | Dendrocitta vagabunda | Haora |
We estimate:
\[ SR_{ijtd} = \sum_{e=-24, e\neq0}^{24} 1(t-LD=e)\beta_{e} + X_{ijdt} + \theta_{i} + \mu_{p} + \gamma_{t} + \epsilon_{ijtd}\] where \(SR_{ijtd}\) is species richness observed by user i on trip j on date t in district d. Each coefficient \(\beta_{e}\) captures species richness relative to the day of lockdown (LD). In the preferred specification, LD = March 24, 2020 and this date is normalized to zero and omitted so that it describes the reference period. If the timing of lockdown is exogenous to pre-period outcomes, then \(\beta_{e}\) should be zero for all \(e<0\). \(\theta_{i}\) is a user fixed effect and controls for ability. \(\mu_{p}\) is a trip type fixed effect for stationary or travelling trips. Since users primarily remain in the same city before and after lockdown, we do not include a district fixed effect. \(\gamma_{t}\) are a set of temporal controls and include date fixed effects and hour fixed effects. \(X_{ijdt}\) is a vector of controls including trip duration and daily precipitation in district d.
sample: stationary trips at home in both periods. data: number of times each user sees each species before and after lockdown. interpretation: proportion of user base seeing different frequencies of species.
In this specification, we aim to estimate the difference in species richness per trip before and after lockdown, compared to same difference in 2019. In other words, we subtract the change in 2019 (the counterfactual) from the 2020 lockdown effect to remove other determinants of species richness that are changing during the window.
To do this, we first select 2020 users with at least 2 trips before and after lockdown. Then we select 2019 users with the same criteria, using March 24, 2019 as the threshold date. These are different users but share similar characteristics.
Formally, we specify the following standard DID regression:
\[ SR_{ijdt} = \beta_{1} [Treatment_{t} \times Post_{t}] + \beta_{2} [Treatment_{t}] + \beta_{3}[Post_{t}] + X_{ijdt} + \eta_{it} + \nu_{p} + \mu_{d} + \gamma_{t} + \epsilon_{ijdt} \]
Where \(Treatment_{t}\) is a dummy for the year 2020 and \(Post_{t}\) is a dummy equal to one for observations after March 24th. \(\beta_{1}\) is the coefficient of interest and describes the change in species richness before and after March 19 in 2020 compared to the same difference in 2019. \(\beta_{2}\) describes the difference in the “before” groups (pre-intervention). \(\beta_{3}\) captures the time trend in the control (2019) group. \(X_{ijdt}\) is a vector of controls including trip duration and rainfall. \(\eta_{it}\) is a user-by-year fixed effect \(\mu_{d}\) is a set of city fixed effects and \(\gamma_{t}\) is a set of temporal controls including date and hour fixed effects. \(\nu_{p}\) is trip type fixed effect and controls for the type of trip: stationary or travelling.
| Difference-in-Difference Estimates | ||||||
|---|---|---|---|---|---|---|
| All Cities | Top 20 | Top 20 | Top 20 | Top 20 | Top 20 | |
| Treat x Post | 0.282 | 1.126** | 0.896** | 1.592*** | 1.187*** | 1.474*** |
| (0.205) | (0.450) | (0.372) | (0.426) | (0.386) | (0.402) | |
| Treatment | 0.158 | -0.194 | -1.193 | 4.316** | -0.594 | 2.297** |
| (0.150) | (0.331) | (1.564) | (2.045) | (1.144) | (0.941) | |
| Post | -0.702*** | -0.440 | -0.737*** | -0.668** | -0.756*** | -0.711** |
| (0.153) | (0.336) | (0.276) | (0.339) | (0.290) | (0.302) | |
| Rainfall (mm) | -0.026 | 0.228 | 0.171 | 0.214 | 0.256* | 0.276* |
| (0.027) | (0.168) | (0.132) | (0.135) | (0.140) | (0.149) | |
| Group Size | 0.049** | 0.069 | -0.023 | 0.185 | -0.012 | 0.184*** |
| (0.023) | (0.059) | (0.050) | (0.122) | (0.051) | (0.062) | |
| Duration | 0.161*** | 0.164*** | 0.170*** | 0.118*** | 0.180*** | 0.200*** |
| (0.001) | (0.003) | (0.004) | (0.004) | (0.004) | (0.005) | |
| Particip. Contstraint | None | 2 Trips | 2 Trips | 2 Trips | 5 Trips | 10 Trips |
| Home | No | No | No | Yes | No | No |
| District FE | Yes | Yes | Yes | Yes | Yes | Yes |
| Trip Type FE | Yes | Yes | Yes | Yes | Yes | Yes |
| Weekend FE | Yes | Yes | Yes | Yes | Yes | Yes |
| Hour Fe | Yes | Yes | Yes | Yes | Yes | Yes |
| User x Year Fe | No | No | Yes | Yes | Yes | Yes |
| Num.Obs. | 39423 | 6442 | 6442 | 3483 | 5112 | 4365 |
| R2 | 0.503 | 0.515 | 0.715 | 0.698 | 0.694 | 0.679 |
| * p < 0.1, ** p < 0.05, *** p < 0.01 | ||||||